Pressed steel car end



lJune 11, 1935. J. P. GALLAGHER I PREssED STEEL CAR END Filed Sept. 22, 1932' TETE' of/WQQ@ ATTORNEY JOHN P. GALLAGHER June 115 1935.- J. P. GALLAGHER PRESSD STEEL CAR END Filed sept.V 22, 1952` 2 Sheets-Sheet 2 ..-1.2. wz), Y

ENTE.

lNvENToR JOHN P GALLAGHER Y WWSQZM v ATTORNEY Patented June 11, 1935A PRESSED STEEL CAB, END

John P. Gallagher, Jersey City, N. J. Application September 22, 1932, Serial No. 634,346

28 Claims.

j The invention relates in genral to a pressed metal panel for use in those parts of a railroad car construction which are subjected to load'V pressures and other stresses which tend to dis- 5 tortthe same, and the invention specically relates to a pressed steel panel which constitutes one of a set of similar panels, or which constitutes a single panel for forming a portion of or an entire wall of arailroad or similar car conlO struction.

More specifically dened, the invention relates to a pressed steel car end or car side of a freight, a box, a gondola, or a hopper car, and which ends and sides will be referred to hereinl5 after collectively as car walls.

A vIt is knownbin the art of pressed steel car ends to form them of one or more sections of corrugated sheets of metal with the sections extending vertically as well as horizontally. In-

20 these known forms the corrugations extend in closely positioned groups and with the corrugations extending parallel to each other, either vertically or. horizontally. YWhen heavily loaded -and exposed to the shocks incidental to the usual service conditions to which cars of this char-` acter are subjected, stresses are set 'up in these known forms of car ends, the stresses being localized at a point somewhere about midway between the verticaledges and-about one quarter to one third up from the bottom line and usually in the vertical medial plane of the car end and diverge therefrom principally downwardly and outwardly towards the lower edge. In the case of the car ends with the vertically disposed cor- :5 rugations, these strains act to .belly or bulge the central portion of the car end outwardly in a curve about the vertical medial line. In the case 'of c ar ends with the corrugations extending horizontally, there is a similar outward bulging l of the car ends about some horizontal line, usually about a lineY positioned approximately one quarter to one-'third of the height of the car end, measured trom the Vlower dge As the lower edge is usually fastened to a rugged 5 end sill, the rcar end thus tends to turn about its lower edge.Vv

It has been found, however, that the usual 7collision shock on any form of steel end car acts to cause it to twist out ot. its normalqplane-and `0 about some diagonal line. For the purpose of counteracting` this tendency. to distort, it has been known to provide diagonal struts which extend from the region adjacent'the center sills towards outer,.upper -edges of the car end. To a certain extent this same condition exists with (ci. 10s-410) reference to the car sides and this outward bellying or bulging of the sides becomes particularly noticeable in the -case of open top cars in the absence of the bracing effect provided by the roof. In the case of corrugated ear ends now known 5 repeated shocks tend eventually to'cause the corrugations to flatten out as the car end as a whole bulges horizontally or vertically as above described and in this' way these car ends eventually become simply more or less flat walls without 10 dany self-reinforcing features.

In addition to the car walls, certain other structural parts of the c ar which do not extend strictly in a vertical direction, such as the drop r doors of gondola and hopper cars, are likewisey subjected in actual use to distorting strain and require the addition thereto of stiflening and reinforcing membersxdisposed to resist thedistrtion of the structural parts from its original confirmation.

'I'he primary object of the invention is to pro-A vide a simple, easily formed, one-piece rugged` structural unit or panel which can be made of sheet metal corrugated and bent to provide an integral self-contained, reinforcing truss construction, and which integral reinforcement will A'tend to resist or-at least minimize deiiections or l bendings of the unit when subjected to the usual f distorting stresses to which structural parts of railroad cars are` subjected while in use.

Broadly, this object of the invention is attained by providing a corrugated. panel construction in i which the corrugations are arranged in the form of a system of single triangular units, sometimes hereinafter referred to as endless' triangular 35 beams, .or multiple of such system of continuous beam units organized to resist bendings of the panel in al1 directions. In the case of the pressed steel car end embodiment of the invention herein illustrated this object is attained by incorporat- 40 ing in a single thin steel panel, Vertical and horizontal types of corrugations arranged and disposed so as to be accommodated in the single sheet Without functionally interfering with each other, and likewise to include therewith diagovnally disposed corrugations 'to form diagonal struts organized and arranged particularly to resist distortions or twistings of the car wall about the diagonal lines above discussed. l

Anotherobject of the invention is to provide a panel wall construction in which the panels 'in and of themselveswill provide the necessary vertical, horizontal and diagonal brace elements usuallyfound in fabricated car constructions, thus featuring an elimination of the usual posts and wall girders.

Still another object of the invention is to provide an improved form of car wall which can be formed of a multiple ofl panels and which panels of themselves will provide vertically ex` tending posts or lines of reinforced area lthrough which roof strains can be transmitted directly to the car body underframe in those cases where a roof is provided and which will coact with hori-L zontally extending corrugations at the top of the side walls to provide a rugged skeleton frame work for maintaining the car body parts rigid relative to each other, even in the absence of the roof structure.

The present disclosure features a panel construction in which operative stresses imposed thereon are transmitted downwardlto the end or side sill to which it is fastened while eliminating or at least minimizing any tendency of the panel or any part thereof to become distorted from its original configuration.

Still another object of the invention is to provide part of a panel sidel or wall construction with reinforcing post-forming-corrugations designed to receive the wooden furring strips for supporting the wooden lining used in certain cars of this character.

Various other objects and advantages of the invention willbe in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of mechanism embodying the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed'.

it is within the scope of this disclosure to useL one of the three panel forms illustrated, for instance the central panel alone may be used ,and

the two outside panels entirely omitted, or their place taken by the usual wooden sheathing, by a flat uncorrugated plate, or by a conventional form of corrugated plate or panel;

Fig. 2 is a horizontal sectional view taken on `the line 2 2 of Fig. 1 looking downwardly as indicated by the arrows;

Fig. 3 is a vertical sectional view taken along the longitudinal medial plane of the car and taken on the line 3 3 of Fig. 1; and

Figs. 4, 5, 6, 7 and 8 are each transverse sectional views taken respectively along the lines 4 4, 5 5, 6 6, 1 1, and 8 8 of Fig. 1.

In the following description, reference will be made particularly to the car end illustrated but it will be understood that the structure described and illustrated will be equally applicable, except for variations in dimensions and other obvious changes, to a car side and that the panel structure herein featured may be utilized in a car structure which has no roof, and that the walls may be inclined tolthe vertical as would be the case with a gondola or hopper car.

In the drawings there is disclosed a car body underframe I0 including a center sill Il, an end sill I2, a floor I3, a roof I4, represented by a roof sheet l5 and otherwise it is intended that the inventive features herein disclosed be illustrated in connection with a car body of conventional form.'

The car end I6 is formed of three substantially rectangular, upstanding panels, designated in Fig. 1 from left to right as I1, I8, and I9. The adjacent vertical edge portions 20 of the panels are disposed in lapped relation as shown in Fig. 2 and the lapped portions are secured together in each case by a line of rivets 2|.' This con-g struction provides a length of doublethickness ofl material between the central panel I8 and the two lateral panels I1 `and I9. This double line of reinforcement extends from the end sill I2 to the roofsheeting I5. The edge portions 20' are substantially flat asshown in Figs. 4, 5, and 6 or may be slightly curved tp form in their coacting l .relation a U shaped channelo as shown at 22 in Fig. 2. The outer vertical edge portions of the panels I1 and I9 are extended beyond the adjacent sides of the car and bent to form corner ,flanges 23 which receive rivets 24 which fasten the flanges to the oar side plates 25.

The bottom edge portions of the panels are bent slightly outward as shown in Fig. 3 from the plane of the major portion of the panel to form end sill engaging flanges 26 which are secured to the end sill I2 bymeans of rivets 21, somewhat following conventional practices in this respect. The upper portions of the panels above the corrugations hereinafter described are at as indicated at 28 and at their extreme upper edges are bent to form roof rengaging flanges 29 underlappingand secured; to' the roof sheet I5 by rivets30.

In spaced relation inwardly`r from the outlining edges of each of the panels is a reinforced area composed of intercommunicating corruga` tions formed by subjecting the initially flat/,plate to a pressing operation with suitably formed dies. The corrugations are for the most part relatively long channels, U-shaped in cross section with the troughsof the channels facing inwardly of the car, and the channels themselves projecting out-f wardly of Ithe remaining fiat or substantially flat portion of the plate. While the panels herein illustrated are for the most part fiat plates, it is obviously within the scope of the disclosure to curve these plates wherever necessary as in curved wall or bottom structures. `It is also obvious that the panel structure herein featured may be bent to form a corner or other angled Ypart of the car structure. l

The design of corrugations herein disclosed inversely 'spaced apart uprights or vertically disposed corrugations 3I and 32 which extend up-4 wardly for any desired rdistance and constitute hollow posts which tend to resist buckling or outward bellying of the panels about horizontal lines. In the form vofv the invention disclosed in connection with the central panel I8 the posts is omitted but may be added if a little more re- `cludes adjacent the edge portion 20 two trans- I inforcement is neededy in the upper region of the reinforced area.

Disposed within the outline of this rectangular to the corrugations 3| and 32 forming posts. 'I'hese diagonal corrugations forml diagonal braces or struts and coact with the corrugations 3I-32 at their ends mutually to reinforce' each other.A Certain of these diagonal corrugations such as those designated -'extend from the upper left to the lower right hand side and othersf ,marked 36 extend from the upper right to the lower left .side of theX-shaped design formed thereby. From. this construction it is seen that the diagonal braces or struts merge at their ends either into the vertical corrugations or into the horizontal corrugations 4 It will be noted from the showing iniig. 1 that these corrugations form a pattern which is a duplicate in whole or in part of a un-it'conilguratiorn comprising four sets of corrugations.` The corrugations of each set extend parallel to each other and are spaced apart a distance greater than their width to provide at areas therebetween. ie corrugations of one set, such as 3I32 extend vertically; those of another set, such as 33-34 extend horizontally; those of a third set, such as 35-35, extend diagonally downward from left to right; and those of a fourth set, such as 36--36, extend diagonally downward from right to left. As the diagonal corrugations 35 and 36 intersect each other, they form between them horizontally spaced apart at triangular areas 31 and 38 and vertically spaced flat double triangular or rectangular areas 3 9 and 40 with the pointsk or right angled corners of these areas spaced equidistant from a point of reference 4I at the central point of intersection of the coruugations 35 and 36. Positioned within each of the areas 39 and 40 is a bullseye or pan-like formof corrugation 42 somewhat parabolic in axial cross section with a slightly llat crown and the axis of this protuberance 42 measured along the line a-a is relatively short, i. e. less than its maximum diameter. In general it will be understood that the corrugated 4reinforcing design as shownin panels I8 and I9 is a duplication of the unit shown inv panel I1. In the unit structure therev are shown grooves 3| and 32, centrally positionedA cylinder or pan 42 and half lengths of 35 and 38 disposed in the form of a square connected end to end and arranged concentric withl the axis af--a of the cylinder 42 and with the annular portions B0 and triangular portions 3lI and 38 disposed in a common plane.

In car wall constructions of the type under discussion there is Pvery little,l if any, bending of the panels in their upper portions and therefore there is no particular need of providing for any `special reinforcing of the upper portion of the panel). For this reason the upper portion of the panel I9 is shown flat at 28 for` the upper third of the panel. As noted above in such structures the loci of the points of thrust of the load which tends to bend the panel is about one-quarter to one-third up from the bottom, or approximately along the line af--a. It is therefore suggested 'in the case of the right panel I9 that the upper third of the reinforcement shown in the central panel be omitted. i

In the showing of the left hand'panel 4I|, the reinforced area has been still further curtailed and the reinforcement confined to the lower third of the panelwhereit is most needed, so that in this suggested form the car wall is for the most part a flat, uncorrugated sheet of `metal and with a small amount of reinforcing corrugation localized where it will do the most good to meet the strains 2,oo4,199'a f dows and `other openings'or may be utilized for other purposes.- Y

'I'he present construction with its formation of inwardly facing hollow posts 3| and 32, lends itself admirably to receive vertically disposed wood furring strips 43, to thelinner faces of which is secured a wood lining 44 herein shown to be th'e conventionaltongue andv groove boards 45 disposed in"l 1orizontally extending lengths in accordance with approved practice. In those cases where the boards extend vertically the furring strips may be contained in the horizontal corrugations 33 and 34 or in either case may be contained in one or mor'e of the diagonal corrugatODS. y

While the posts 3| and 32 may extend almost to the top o'f the panelas shown in the case of the middle panel I8, and as shown in Fig. 3, it is herein suggested that these posts forming corrugations be of less height and may terminate at and merge into the upper ends of'the lcorrugations 36-36 defining the upper end of the corrugated portion of panel I9, or may extend above the corrugated portion for any desired or required distance as indicated in the case of the panel I'I.

It will be further understood that the panel as herein disclosed maybe utilized as a repair part) of a.conventional box Icar now in general use, and in-which case one of the panels of the type herein disclosed is positioned where it will be of the maximum value and, in the case of a Icar end, is usually centrally positioned, as is the panel I8. f

It is to be understood that in place of the three-y panel type of pressed steel end herein disclosed, the entire end may be made of a single sheet pressed to fo'rm and in which oase, of course, the lapped joint structure at 22 will be omitted. It is also suggested that in those cases where there is no particular need for providing rigidity to the upper portion of the wall, the lower portionl may be formed of a single sheet provided with the vertical, horizontal and ldiagonal reinforcing grooves herein featured leaving the upper portion as a at sheet panel. As the usual distortion is along 'the diagonal lines corresponding to the direction of 'the'. members 35 and 36, it is herein `suggested* that a simpler construction may be provided,by utilizing the integral diagonal braces herein disclosed, omitting either or both of the vertical and horizontally extending corrugations.

It is also obvious thatthe diagonal corrugations usually imposed upon the car ends. It is obviousthat the space 28 may be utilized to contain win'- 33- 34 will extend vertically forming short posts corresponding to the posts 3I-32 and the long channels 3I-32 will extend horizontally andiorm y long girders at the top and bottom of the gondola By means of the disposition of the corrugations herein disclosed in their vertical, horizontal and diagonally inclinedrelations, it is possible to provide a cheap panel structure which can be easily pressed or stamped to shape,- which can be used alone or assembled with other panels to form an integrally braced structure without necessity of providing separate bracing elements thus economizing in both the cost of material and inthe labor charges incidental to fabricating the main structural part with its reinforcing additional parts. A car wall, and particularly a car end of the character herein disclosed, provides all of the resistance to bending about vertical and horizontal axes such as are provided by known structures, and in addition thereto provides, without additional material, a structure. which will tend to resist the more prevalent diagonal twists to 4which cars, and particularly freight cars are subjected during starting and stopping and other shocks.

I claim:

1. An upright structural part of a car body adapted to resist loads imposed thereon in a horizontal direction, and which loads are usually localized at a point thereon intermediate its upper and lower'edg/es, said structural part comprising a one-piece sheet of metal provided in Ispaced relation to its outlining edges with long corrugations, vsubstantially U-shaped in cross ,section and forming vertical posts, other corrugations opening at their ends into and connecting the posts at top and bottom thereof to form horizontally extending struts and coacting with the posts to form a rectangular continuous reinforcing frame spaced inwardly from the outlining edges of the sheet, and certain other corrugatons posi-tioned between and extending at an angle to the posts to form diagonal struts at opposite ends of the posts, intersecting each other to form an X located in the frame in spaced relation to one end of the frame; l

2. A pressed metal panel constituting a part of a car construction, comprising a flat sheet formed with a plurality of projections extending integrally from ont side thereof and spaced from opposite outlining edges to leave the edge portions uncorrugated and adapted to receive fastening means, said projections arranged in a pattern which includes duplications of a yunit configuration comprising a cylindrical pan-shaped ele,- ment having an axial length measured vperpendicular to the plane of the sheet less than its diameter and four straight elements each U- shaped in cross section and of uniform crosssectional connguration from' end to end arranged l as the sides of a square and connected end,to

end, said square being concentric with, encircling and spacedfrom the cylindrical element with the portions of 'the panel between the cylindrical element and the square disposed in the plane of the at edge portions. I

3,v A pressed metal panel constituting a part of a car construction comprising a flat sheet formed with a plurality of corrugations projecting integrally from one side`thereof and spaced from "opposite outlining edges to leave opposite edge portions flat and adapted to receive fastening means, said corrugations arranged in a pattern which includes duplications of a unit conguraton comprising four projections arranged symmetrically about a point of reference, each projection including a 4*substantially fiat right angled corner and all four corners spaced equiaooaioo arranged in pairs on opposite sides of said point and a side of each projection extending parallel to the contiguous side of the next adjacent projection, and the portions of the sheet between said projections contained in the plane of the opposite edge portions.

4. In al device of the class described, the combination of a pair of metal'panels having vertically extending edges and disposed side by side to form a portion of a car body wall, each panel comprising a single pressed metal sheet corrugated in spaced relation to its vertically extending edges to form reinforcing members, certain of which extend vertically and certain other of which extend at an angle to the vertical, the vertical reinforcing members constituting integral posts extending substantially from top to bottom of the panels, the adjacent vertical edges of said panels being at and with flat sides Secured together in lapping relation to form a double thickness of metal constituting a vertically disposed'stiiening member positioned between and extending parallel to the adjacent posts formed by the corrugations of the panels.

5. In a car body wall construction, the combination of a plurality of sheet metal panels disposed with their adjacent vertical edges 'lapping and secured together to form the wall, and to provide a line of double thickness of material extending vertically from top to bottom of the wall, certain of said panels provided with integral vertically extending corrugations positioned on opposite sides of and extending parallel to said line and coacting therewith to form a series of vertically extending reinforcements constituting hollow posts at opposite vertical edges to brace the wall from top to bottom at such edges, said posts having structural strength sufficient to provide the requisite rigidity of wall without the necessity of employing the usual car side or corner posts and said panel provided with integral horizontally extending corrugations opening into and connecting respectively the tops and bottoms of said hollow corner posts.

6. A sheet metal car side Lun't corrugated to form a series of triangular beams interconnected to forma single endless corrugation.

7. A sheet metal car body wall construction provided with corrugations forming a plurality of identical patterns, each of said patterns forming an endless beam of substantially triangular form and certain of said beams opening into the next adjacent beam at their -adjacent angles.

8. A sheet metal car end formed of a plurality of separate panels secured together, each panel being of rectangular form and being corrugated with vertically and horizontally extending corrugations forming a rectangular outlining frame spaced a slight distance inwardly from the edges of the panel to leave an outlining flat fastening flange and the portion of the panel within the frame being corrugated with diagonally extending corrugations opening at their ends into the 'sides of 'the frame and coacting therewith to provide apluralityof endless beams.

9.. In a car wall construction, the combination of upstanding corner posts, a sheet metal construction having opposite upright edges iianged to provide a casing lapping two sides of each post, the lower portion of the construction being corrugated to provide a reinforced area between the posts, the corrugations forming a line of reinforcing beams disposed close to each other and `each beam vbeing of triangular form with the three distantv from said common` point of reference andiy sides opening into each other end to end.

10. In a car wall having outwardly pressed reinforcing corrugations coacting to form an end- -less channel on 4the inner side .of the wall, certain ofv said corrugations combined to form a plurality of horizontally spaced and vertically ex'- tending posts extending substantially the full height of the car wall, other corrugations extending horizontally, connecting the posts in pairs and constituting struts, and still other corrugations extending diagonally between the posts and mutually intersecting each other at their midlengths to form X-shaped braces between the posts.

' ll. A sheet metal car end corrugated to form vertical and horizontal corrugations connected end to end to form a rectangular frame, and also corrugated to form diagonal corrugations forming a lattice-work connection between opposite sides of said frame.

12.,A metal panel constituting a u nitof a car side provided with a plurality of interconnected corrugations, two 'of said corrugations extending parallel to each other, a third corrugation connectingtand having its ends opening into said parallel corrugations and two other corrugations intersecting each other at their mid-portions to form an X, with one end of each of said X-forming corrugations openinginto the parallel and third corrugations at their intersecting corners and having their opposite ends opening into the parallel corrugations in spaced relation to said COI'IISIS.

1.3.A metal panel constituting a unit of a car side provided `with -four corrugations each of substantially uniform cross sectional formfrom end to end, arranged in the form of a square and each one opening at opposite'ends into the adjacent corrugations to form an endless corrugation, and a fifth corrugation oi' substantially frusto-conical form disposed within the outline of the endless corrugation and spaced therefrom.

14. In a. railroad carwall a rectangular panel having a at outlining edge portion of substantially uniform width to form fastening flanges about the four vedges of the panel, the area within said ilat iianges being provided with corrugations, with ,the corrugations constituting duplicates of a single` pattern including straight lengths connected at their ends into an endless design and having bulls eye projections formed between and spaced from certain of the straight length'corrugations and with an uncorrugated area surrounding the projections. I

' 15.7A sheet metal car end provided with corrugations to form a reinforced area, with the corrugations disposed to form the area into, a plurality oi! triangular endless corrugations with uncorrugate'd triangular areas within the endlessntriangular corrugations and a'single corrugation common to two triangular endless corrugations.

16.A metal panel'provided with a plurality of straight lengths oi' corrugations with four of fsaidv corrugations arranged in end to end rela; .tion and/ opening at their ends one into another to form a single rectangular endless corrugation, other of said corrugations extending diagonally between the corrugations forming the endless corrugation, said corrugations coacting to form a plurality of endless corrugations of triangular form with substantially ilat, uncorrug-ated areas of triangular form between the triangular endless corrugations.' r t 17. A metal panel provided with a plurality ofK straight lengths of corrugations with four of( said corrugations arranged in end to end relation and opening at their ends one into another to form a rectangular endless corrugation, other of said corrugations extending diagonally between and each connecting two adjacent lengths of the corrugations forming the endless corrugation, and said corrugations coacting to form a plurality of endless corrugations of triangular form.

y 18. A metal panel provided with a plurality of corrugations, two of said corrugations extending in parallel relation, a third corrugation extending between and having its opposite ends pening into the parallel corrugations and two other corrugations` forming a V with their adjacent ends opening into said third corrugations and having their other ends opening into said parallel corrugations, 19. A metal panel provided with a plurality of straight corrugations, four of saidcorrugations being connected end to end to forni a rectangular endless corrugation, four other diagonal corrugations having their opposite ends opening into the endless corrugation and forming two pairs, with the corrugations of each pair forming an X construction, said X constructions disposed With their adjacent ends opening into each other at their junction. with the endless corrugation. y

,20. A rectangular sheet metal panel provided adjacent its four outlining edges with a continuous corrugation forming an integral reinforcing frame and said panel also provided within said frame with other straight corrugations extending in pairs, each pair forming a V extending uninterruptedly between different sides of the eontinuo'us corrugation and having.l their opposite ends opening into said continuous corrugation.

2l. A metal panel provided with a reinforced area formed of .straight lengths oi corrugations, disposed in relative angular relation, with their channels opening at their ends into each other and coacting to iorm a plurality of triangular endless corrugations, said triangular endless corrugations being of different sizes and with a part of a larger triangle `forming part of a smaller triangle.

22. A sheet metal panel forming a structural elementfor a car and provided with a plurality n eye projections and the other corrugations'being straight of uniform cross-sectional configuration throughout their respective lengths and spaced from the bullseye projections with an annular uncorrugated area, surrounding each bulls eye Vprojection and disposed between the same and the adjacent straight corrugations. t i 23. A metal panel provided with a plurality of straight corrugations, four of said corrugations being connected end to end to form a rectangular endless corrugation, four other diagonal,v corru- 'gations having their opposite ends opening into Athe endless corrugation and forming two pairs, with the corrugations of each pair forming an /X construction, said X constructions disposed with their adjacent ends opening into each other at their junction with the endless corrugation and a circular pan-like corrugation centered between and spaced from the two X constructions.

24. A car end constructed of sheet metal in with straight corrugations spaced from and thus not intersecting the circular corrugation to leave a, substantially flat uncorrugated area between the circular and straight crrugations.

25. ln a car Wall construction, a sheet metal unit having a pan-like form of corrugation spaced from its edges,v said projection being approximately parabolic in axial cross section and having a substantially iiat crown portion.

26. In a corrugated sheet of metal having four straight groovesv formed integral and coacting to form a quadrilateral figure, and a pan-like form of corrugation centered in the space formed by said grooves, said pan-like corrugations being somewhat parabolic in axial cross section, with a slightly fiat crown and having its axis less than its diameter.

27. A sheet of corrugated metal having straight grooves forming the corrugations and projecting to one side of the plane of the uncorrugated portions of the metal sheet, said grooves interconnected to form a lattice effect, and invwhich certain of the grooves coact to form a continuous corrugation of triangular form.

28. A one-piece panel of sheet metal provided in spaced relation to its outlining edges with halftube forms of corrugations interconnected to form a single endless channel, defining a substantially at corrugated area, said area at every cross section thereof intercepting a reinforcing Wall extending substantially perpendicular to the plane ofthe corrugated area thereby tending to resist bending oi the sheet about all possible hinge lines, and said area containing an additional corrugation including an endless Wall extending substantially at right angles to said plane and the portion of the panel surrounding said additional corrugation being flat and uncorrugated. l

JOHN P. GGlER. 

